| 摘要 |
Migration of air through a flanged connection into piping containing a gas under negative pressure is prevented by disposing concentric inner and outer gaskets between the flange faces, so as to form an annular chamber into which a blanketing gas is introduced at a pressure higher than atmospheric. Air tending to migrate through the outer gasket is blocked by the higher-pressure blanketing gas in the annular chamber. The blanketing gas pressure is maintained at a level higher than atmospheric notwithstanding any fugitive emissions through the outer gasket. The annular chambers of multiple flanged connections may be interconnected to blanket multiple flanged connections using a single source of blanketing gas. The blanketing gas may be the same type as the gas under negative pressure. In sour service applications, an inert blanketing gas may be used to prevent leakage of sour gas to atmosphere through flanged connections. In alternative embodiments, the principles of the invention may be adapted for use with other types of connections including threaded piping connections, and for use with piping carrying liquids.
|
